Cadherins are calcium dependent cell adhesion molecules. They preferentially interact with themselves in a homophilic manner in connecting cells; cadherins may thus contribute to the sorting of heterogeneous cell types. The cadherin molecule Cadherin-17 is also known as liver-intestine cadherin or intestinal peptide-associated transporter HPT-1. Cadherin-17 may have a role in the morphological organization of liver and intestine. It is also involved in intestinal peptide transport. The Cadherin-17 structure is characterized as having an extracellular domain with 7 cadherin domains, a single hydrophobic transmembrane domain and a short C-terminal cytoplasmic tail. Only one human Cadherin-17 isoform is known, Genbank® Accession No. NM—004063. Cadherin-17 has the accession number Q12864 in the SWISS-PROT and trEMBL databases (held by the Swiss Institute of Bioinformatics (SIB) and the European Bioinformatics Institute (EBI) which are available at www.expasy.com). The mouse Cadherin-17 orthologue (Q9R100) shows 76% identity to the human Cadherin-17.
According to SWISS-PROT, Cadherin-17 is expressed in the gastrointestinal tract and pancreatic duct. It is not detected in kidney, lung, liver, brain, adrenal gland or skin. Cadherin-17 expression has been reported in gastric cancer (see, for example, Ito et al., Virchows Arch. 2005 October; 447(4):717-22; Su et al., Mod Pathol. 2008 November; 21(11):1379-86; Ko et al., Biochem Biophys Res Commun. 2004 Jun. 25; 319(2):562-8; and Dong et al., Dig Dis Sci. 2007 February; 52(2):536-42), pancreatic cancer and colorectal cancer (Su et al., Mod Pathol. 2008 November; 21(11):1379-86) and hepatocellular carcinoma (Wong et al., Biochem Biophys Res Commun. 2003 Nov. 21; 311(3):618-24). International Patent Application WO2008/026008 discloses Cadherin-17 as a marker for colorectal cancer and as a biological target for therapeutic antibodies and other pharmaceutical agents.